1. Field of Invention
The present invention relates to electronic systems for monitoring sports contests.
2. Description of the Prior Art
Several types of indicators exist for assisting officials monitoring events of interest, particularly those along lines or boundaries, at sports contests. Examples are those for determining whether a tennis ball lands in or out of play during tennis matches. One type of indicator is an electronic-laser indicator, as set forth in U.S. Pat. No. 3,810,148, of which Applicants are two of the inventors. Other types of line indicators include those utilizing pressure sensitive tape as the line or boundary and those based on the principle of detection of magnetic particles in the ball.
In the event that an official's call is disputed, the indicator signal may be consulted. It would be desirable to verify the determination of both the official's call and the indicator signal in the event the two differ, or a continued dispute in the event the two are the same. Television instant replay systems have been extensively used in sports events, and would appear suitable for this purpose.
Determination of the time of impact of the ball near a boundary, however, creates a problem for both photographers and television replay equipment operators. Unless the replay equipment is activated at the proper time to retain the impact of the ball on or near the boundary, the event of interest may be missed or improperly recorded. Further, other problems exist. For example, in some sports the ball often moves so swiftly that even during slow motion or stop action instant replay the ball appears as an elongate or stretched blur rather than as a distinct, discrete object.